1. Field of the Invention
The present invention relates to a method for rendering water-insoluble materials water-soluble. More particularly, the invention pertains to a method for making substantially water-insoluble bioactive materials, such as drugs, more water-soluble by forming non-covalent complexes with polymers which are soluble in both water and organic solvents.
2. Description of the Prior Art
It is known in the art that a wide variety of bioactive materials are either completely or substantially insoluble in water. It would be most advantageous if such materials could be made more water-soluble while maintaining their bioactive. In the prior art, when a promising drug candidate was found to be insufficiently water-soluble, research focussed on molecular alteration of the compound to produce a water-soluble analog, such as its salt form. However, many times such is not possible and a compound which has beneficial properties must be abandoned.
Other attempts at solubilizing drugs include, for example, U.S. Pat. No. 5,160,734 which discloses complexing a poorly water-soluble drug with a polyoxypropylene-polyoxyethylene block copolymer. A complex is formed by blending the polymer, drug and ethanol followed by granulation with lactose and vacuum drying. U.S. Pat. No. 5,030,448 suggests taking advantage of the hydroplhilic-hydrophobic portions of a polymer which is surface active. This system requires a hydrophobic central moiety instead of one which is water-soluble. U.S. Pat. No. 2,898,267 shows the use of polyalkylene oxide adducts of C.sub.9 -C.sub.22 alkyl alcohols to form emulsions. U.S. Pat. No. 4,904,466 shows polymers which form gels at low water concentrations by using a C.sub.8 -C.sub.20 group containing polyethylene ether surfactants in capped polyether polymer gels for drug delivery. U.S. Pat. No. 4,511,563 discloses analgesic gels using block copolymers of ethylene oxide and propylene oxide. Only mixtures are shown. None of these suggest a mechanism for making a water-insoluble component water-soluble.